Electrolytic cell



April?, 1970 H. HARNlscH ETAL ELEGTROLYTIC CELL 2 Sheets-Sheet 1 Filed April 4 196'? April 7, 1970 H. HARNISCH ETAL 3,505,198

ELECTROLYTI C CELL Filed April 4, 1967 2 Sheets-Sheet 2 United States Patent O Int. C1. B1k 3/00 U.S. Cl. 204-275 5 Claims ABSTRACT OF THE DISCLOSURE An electrolytic cell sealed in gas-tight and liquid-tight fashion and formed of a cell tank, -a supporting means and a cell cover, comprising a box-shaped cell tank, open at its top and having associated to its upper rim portion a flange directed outwardly, a supporting frame secured to the top of the cell tank and receiving an electrode system and a cover mounted in gas-tight and liquid-tight fashion on the supporting frame and including a duct receiving current supply bolts and a second duct receiving a bursting disk.

The present invention relates to an electrolytic cell for the electrolytic separation of metals or metal compounds from an aqueous solution of a metal salt. The electrolytic cell can more particularly be used for the anodic oxidation of manganese salts, preferably manganous sulfate, in a sulfuric acid solution using lead or lead alloy anodes. Needless to say the electrolytic cell can also be employed for applications other than mentioned above.

Electrolytic cells are generally found to be similar in design. They are customarily formed of a container receiving the starting material to undergo electrolysis, which is supplied in the form of a liquid or melt, and the electrodes which are immersed in the solution or melt. The container is either open or closed at its top. In addition thereto, the electrolytic cells have associated Lmeans adapted to the particular conditions prevailing, such as diaphragms, means for supplying the reactants and means for removing reaction product, means for regulating the temperature of the starting materials, and similar means.

The process mentioned above for the electrolytic production of manganese dioxide cannot be carried out under commercially attractive conditions in any of the conventional electrolytic cells. The reason is that this process is carried out at relatively high temperatures of the electrolyte, which lie between 80 and 100 C., conveniently between 90 and 98 C., and at a relatively low current density of 0.5 to 1.5 amperes per square decimeter, particularly 0.7 to 1.3 amperes per square decimeter. Gaseous hydrogen as the electrochemical equivalent of the manganese dioxide formed at the anode is found to be evolved at the cathode. The simultaneous evolution of corresponding amounts of oxygen results in the electrolytic eiliciency being reduced. If the process were carried out in an electrolytic cell open at its top and having a suction blower associated therewith, the high partial pressure of steam inside the gas chamber above the electrolyte would be found to give rise to considerable loss in entrained steam and accordingly to considerable loss in calorific energy. As a result of the low current density, the Joulean heat generated inside the electrolyte would be far from equalizing the loss in caloric energy, and the' heat accumulated in the electrolyte would be required to be used for equalizing this. This again would result in the electrolyte travelling through the cell being subjected to relatively large temperature changes, and non-uniform product and losses in yield would be obtained.

The electrolytic cell of the present invention has now been found substantially to avoid losses in steam and in caloric energy. Apart from the electrode system, which does not form part of the present invention, the electrolytic cell is formed of a cell tank, a supporting frame for the electrode system and a cell cover. More particularly, the substantially box-shaped cell tank open at its top and having associated to its upper rim portion a llange projecting outwardly and surrounding the tank, has mouted in gas-tight and liquid-tight fashion a supporting frame receiving the electrode system, the supporting frame being sealed in gas-tight and liquid-tight fashion by means of a cover mounted thereon and including a duct for receiving the current supply bolts and a second duct receiving a bursting disk. All these elements which are contacted Iby the electrolyte are coated on the inside with a chemically resistant and electrically insulating lining, c g. a rubber or plastic lining.

The supporting frame preferably has a cross-section similar to that of a U lying on its side opening outwardly and provided with vertical reinforcing ribs, and the lower flange is preferably designed to widen towards the inside of the supporting frame, which serves to receive and support the electrode system.

Between the ange disposed at the upper rim of the cell tank and the outwardly projecting portion of the lower llange forming part of the supporting frame there are preferably arranged (a) an elastic packing extended towards the inside of and surrounding the supporting frame, and (b) a rigid pressure bar extended towards the outside of a'nd surrounding the supporting frame.

The same constructional arrangement is found between the upper flange of the supporting frame and the cell cover.

The elastic packaging and rigid pressure bars may have a rectangular cross-sectional area. The packings are preferably formed of rubber or plastic material and the pressure bars are preferably made of =wood or plastic material. The pressure bars are intended to prevent the packings from being exposed to inadmissibly high pressure.

The cover rim portion resting onthe packing and pressure bar is reinforced.

Rubber or plastic, elastic, cone-shaped 'bellows which surround in gas-tight manner both the current supply bolts and the ducts receiving them ensure that the current supply bolts forming part of the electrode system can be passed in gas-tight manner through the ducts seated in the cell cover.

The cell tank is preferably covered on the outside with a heat-retaining layer and provided with reinforcing ribs, a material inlet, an overflow and a discharge pipe.

The apparatus of the present invention is shown diagrammatically in the accompanying drawings, wherein- FIGURE 1 is a side elevational view of the electrolytic cell taken along line I-I of FIGURE 2;

` FIGURE 2 is a cross-sectional view of the apparatus taken along line II-II of FIGURE 3;

FIGURE 3 is a top plan View of the apparatus; and FIGURE 4 is a representation on an enlarged scale of the upper left hand corner of FIGURE 2.

Cell tank 9, which is disposed to repose on supporting grate 23, has its outside cover with a heat-retaining layer 14, is reinforced by means of ribs 16 and 2.5, and its inside lined with a chemically resistant and electrically insulating lining 19. Inlet pipe 11 through which the electrolyte is supplied, overilow pipe 12, discharge 3 pipe 13 and the upper side of flange 17 forming the upper rim portion of cell tank 19 are lined in corresponding fashion.

Flange 17, above which there are placed an elastic packing 8 and a pressure bar 10, is intended to receive supporting frame 7 reinforced by means of vertical ribs 26, the frame 7 together with ange 18, which projects inwardly, forming a support receiving the electrode system. The upper side, underside and inside are coated with a chemically resistant and electrically insulating lining 22 in a manner similar to cell tank 9.

The cell cover 1 which is the upper terminal of th electrolytic cell is designated so as to rest with its reinforced rim portion 214 through an interposed elastic packing 6 and a pressure bar 21 on supporting bar 7. The underside of the cell cover is coated with a chemically resistant and electrically insulating lining 20. The lining 20 is extended so as to include ducts 2, mounted on the top of the cover and receiving bolts 3, supplying current to the anode, and bolts 3 supplying current to the cathode, and tubular opening 15 which receives a bursting disk. The cone-shaped bellows 4, which surround the current supply bolts 3 and 3' and duct 2, ensure that the ducts are reliably sealed.

'The electrolytic cell of the present invention has been found to iWork very reliably. Only small quantites of calorifc energy are lost. Gas evolved by the electrolysis, which substantially consists of hydrogen with only minor proportions of oxygen, is found, at the operating temperature contemplated, to be so strongly diluted with stem that explosive outbreaks are not like 1y to occur.

We claim:

1. In an electrolytic cell sealed in gas-tight and liquidtight fashion and including the Afollowing structural elements: (1) an electrolyte-receiving cell tank, (2) an electrode-supporting frame which has an upper and a lower ange arranged thereto and is secured in gas-tight and liquid-tight fashion to the top of the cell tank, and (3) a cell cover including ducts receiving current supply bolts and a further duct receiving a bursting disk, all of the said structural elements having a chemically resistant and electrically insulating coating applied to their inside, the cell cover being substantially box-shaped,` open at its top and having associated to its upper rim portion a I.flange directed outwardly so as to surround the tank, the improvement according to which the supporting frame is designed to have a cross-section similar to that of a U lying on its side, opening outwardly and provided with reinforming ribs, the lower flange extending towards the inside of the supporting frame, and wherein an elastic packing disposed towards the inside of the supporting frame and a rigid pressure bar disposed towards the outside of the supporting frame are arranged between the ilange of the cell tank and the flange of the supporting frame, and wherein an elastic packing disposed towards the inside of the supporting frame and a rigid pressure bar disposed towards the outside of the supporting frame are arranged between the upper flange of the supporting frame and the cell cover.

2. An electrolytic cell as set forth in claim 1 wherein for the gas-tight passing of the current supply bolts through the ducts there are provided elastic, cone-shaped bellows, which make a gas-tight encloure about current supply bolts on the one hand and about the ducts on the other hand.

3. An electrolytic cell as set forth in claim 1 wherein the cell tank is coated outside with a heat-curbing coating and is provided with reinforcing ribs, intake ducts, overflow ducts, and discharge ducts.

4. An electrolytic cell as set forth in claim 1 wherein the elastic packing and the pressure bars have a rectangular cross-section.

5. An electrolytic cell as set forth in claim 1 wherein the edge of the lid resting on the backing and the pressure bar is reinforced.

References Cited UNITED STATES PATENTS 1,632,285 6/1927 Georgi 2014-278 3,104,308 9/ 1963 Wilson 204--275 3,116,228 12/ 1963 Talboll 204-266 3,203,882 8/1965 Forbes 204-278 HOWARD S. WILLIAMS, Primary Examiner S. S. KANTER, Assistant Examiner 

